Curved expander rolls



May 24, 1955 w. a DEAN 2,708,785

' cuRvEp EXPQNDER ROLLS Filed Feb. 8, 1952 2 Shee ts-Shet 1 May 24, 1955 w DEAN 2,708,785

CURVED EXPANDER ROLLS Filed Feb. 8, 1952 2 Sheets-Sheat 2 United States Patent 0 CURVED EXPANDER ROLLS Walter Dean, Taunton, Mass., assignor to John Douglas Robertson, Taunton, Mass.

Application February 8, 1952, Serial No. 270,581

6 Claims. (CI. 26-63) This invention relates to improvements in expander rolls for flexible sheet materials. More particularly it relates to expander rolls of the general type wherein a flexible surface sleeve of rubber, or the like, is mounted for rotation about the axis of a rigid curved axle whose opposite ends ordinarily are adjustably fixed, with the roll disposed transversely of and in engagement with a travelling sheet. The draft of the sheet causes rotation of the curved roll, and rotation of the curved roll effects width-wise expansion of the sheet, assuming that the sheet approaches the roll at its concave side and leaves the roll at its convex side. It should be understood, however, that the curved rolls may be employed for reducing the width of engaged travelling sheets, such as in the process of making creped paper, for example, in which case a travelling sheet would approach the curved roll at its convex side and leave the roll at its concave side.

The invention provides improvements in the curved axles of curved expander rolls, whereby the flexible surface sleeves of the rolls are more readily rotatable on their curved axles.

Prior curved expander rolls of the general type disclosed in Patents Nos. 2,393,191 and 2,562,949, granted respectively January 15, 1946, and August 7, 1951, to John D. Robertson, have employed a multiplicity of bearing units between their rigid curved axles and their flexible surface sleeves, and each bearing unit has included an inner bearing element non-ro-tatably mounted on the curved axle and an outer coacting bearing element which has been rotatable with the flexible surface sleeve. In the prior curved expander rolls of the general type disclosed in said Patent No. 2,393,191, the coacting bearing elements of each bearing unit have been inner and outer ball races of a ball hearing which, due to the number of ball bearings required, have added considerably to the cost of the expander rolls.

The prior plain bearing types of curved expander rolls frequently have had a flexible surface sleeve engaged over a series of cylindrical spools distributed on and along a cross-sectionally round curved axle, with the spools in direct bearing contact with the axle and rotatable thereon in response to rotation of the surface sleeve. The interior diameter of the spools necessarily have been greater than the diameter of the axle to enable slipping of the spools to distributed positions along the curved axle, and each spool could have only a point-bearing contact on the longitudinally curved, cross-sectionally round axle. This point-bearing contact of the spools on the axle has caused relatively rapid wear of the axle at the bearing points, and the material abraded from the axle has mixed with the lubricant within the roll to produce a lapping compound which has acted to materially increase the abrading action. The said Robertson Patent No. 2,562,949 discloses an improved plain bearing curved expander roll which is not subject to the mentioned rapid wear because two-part cylindrical bearing units are eniployed of which one part is fixed to the axle and the other rotates 0n the fixed part.

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I an improved curved axle whose curvature is attained by a series of relatively slight bends at spaced locations along the axle, thereby to leave cylindrical, cross-sectionally round bearing portions between the bends for direct bearing coaction with bearing elements mounted within and rotatable with the flexible surface sleeve. Ac-

cording to the invention, an initially straight cross-sec t'ionally round axle element is annularly grooved at predetermined spaced locations along the axle element to provide spaced regions of weakness between intact cylindrical portions of substantial length. When this straight axle element is subjected to bending stresses, to impart a desired curvature to the axle, relatively slight bends occur at the grooved regions of weakness and the intervening cylindrical portions remain cylindrical for effective bearing coaction directly with bearing elements arranged on the curved axle in end to end relation. The flexible surface sleeve engages elastically over the bearing elements, tying them together for rotation with the sleeve as a unit.

Another object of the invention is to provide a curved expander roll wherein a curved rigid axle is bent at a multiplicity of spaced locations along the roll to provide it with a desired curvature and to provide a multiplicity of straight bearing portions between the spaced bends, whereby the straight bearing portions are adapted to coact directly with hearing elements mounted rotatably on the curved axle.

It is, moreover, my purpose and object generally to improve the structure and operative efliciency of curved expander rolls, and more especially such rolls which have their flexible surface sleeves mounted for rotation on their rigid curved axles with bearing elements interiorly of the surface sleeves and rotatably mounted directly on spaced cylindrical bearing surfaces of the axle.

In the accompanying drawings:

Fig. 1 is a side elevation of a curved expander roll embodying features of the invention, the central portion of the roll being broken away, and one end portion of the roll being partly in medial vertical cross-section;

Fig. 2 is a view of one end portion of the roll of Fig. 1 on a larger scale, the axle being shown in elevation, and the other elements of the roll being in medial vertical cross-section;

Fig. 3 is a view similar to Fig. 2 but showing another embodiment of the invention wherein needle-type roller bearings intervene between cylindrical portions of the axle and spaced roll sections or sleeves which, with spacing elements, support the resilient surface tube or sleeve of the roll;

Fig. 4 is a cross-sectional view on line 4-4 of Fig. 3, and

Fig. 5 is a view similar to Fig. 3 but showing still another modification.

Referring to the drawings, the axle 10 may be a crosssectionally round rigid rod or bar of metal which, prior to being bent, is provided with a multiplicity of annular grooves 12 at predetermined spaced locations along the rod or bar. The grooves 12 represent spaced regions of weakness at which the rod or bar bends when subjected to bending stresses in the process of shaping the rod or bar to provide a curved roll axle 10 having a predetermined curvature. The spacing of the grooves 12 is such that substantial stright cylindrical bearing portions 14 intervene between the grooves, and the number of grooves 12 distributed along any particular roll axle preferably will be such that the desired total curvature of the axle may be attained with onlya relatively slight bend at any of the individual grooves 12. In the drawings, the eed bends are somewhat exaggerated for clcarness showing. Actually, the bend at any groove r2 may be so slight that bearing elements 16 having internal diametcr only slightly greater than the larger diameter portions of the axle ll can he slid along the axle in so sion until a bearing element 16 is in bearing with each cylindrical bearing portion 14.0? the axle, an additional bearing element 16 is provided at each end of the roll in hearing coaction with the cylindrical portions 14 of the axle adjacent to and outward of the end-most grooves 12.

When the bearing elements 16 of oflwood, or of other materials suitable f ll'te cylindrical bearing portions 14 of the axle, reqturcd to requisite looseness of the bearing elements to permit them to be threaded on the cu "is, does not materially affect the eificiency of the be elements 16. However, such looseness woul be impracticable where ball bearings or needle bearings are to be employed. In such cases, longer annular grooved regions are provided between the bearing portions oi the 2,

so that a'ball bearing unit, or a roller bearing unit, may operatively fit the larger diameter of the axle and be moved along the curved axle by passing from one bearing portion of the axle into one of the annular grooves before being engaged around the next succet ing bearing portion of the axle. Figs. 3 and 4 show needle-type roller bearing units 17 whose roller-retaining elements 17' are fixed within bearing elements in, one bearing unit 17 in each bearing element 16". The rollers of each bearing unit 17 nicely fit the cylindrical bearing portions 14 of the axle it), with spacing sleeves l9 maintaining the hearing elements it? in spaced relation. The annular grooves 12 in axle 1d are made slightly longer than the roller bearing units 17, so that a bearing element 1-13, with roller bearing unit l7 fixed therein, may be slipped on the axle with the rollers f the bearing unit fitting nicely around a cylindrical i of the axle. "the bearing element and bearing unit may be slid along the cylindrical portion of the axle until the roller bearing unit enters an adjacent annular groove E2 in the axle wherein it may be tilted into axial alignment with the next succeeding cylindrical portion of the axle preliminarily to being s onto that next succeeding cylindrical portion of axle. Hence the bearing elements 16, each with a roller bearing unit therein, may be slid from one to another of the bearing portions 14 of the axle during assembly of the curved roll notwithstanding that the bearing units nicely fit the larger diameter portions of the axle.

The spacing elements 19, in the Fig. 3 embodiment preferably overlap annularly reduced end portions of adjacent bearing elements 16, as at 19', so that the spacing elements 19 are held against radial displacement. The overlapping engagements of the sleeves at the locations 19' are relatively loose to permit the needed slight adjustment between each sleeve 39 and the adjacent bearing elements 16' during rotation of the bearing elements and sleeves about the curved axle The outer surface area of each spacing sleeve 1; should approximate the outer surface area of each bearing element 16.

If desired, the bearing elements 15' of Figs. 3 and 4 may be made long enough to extend into end to end engagement as illustrated at E6" in Fig. 5, in which case no spacing sleeves 19 are necessary. Because the internal diameter of these longer bearing elements 16 of Fig. 5 is substantially greater than the diameter of the cylindrical bearing portions 14' of the axle H the bearing elements 16" do not interfere with the mentioned tilting of a roller bearing unit 17 in an annular groove 12 of the axle.

In the illustrated embodiments of the invention, the

bearing elements 16, 16, 16" are maintained against 5 any appreciable travel along axles 10, It) by rigid cylindrical sleeve members 18 which project inward from the ball bearing units 20 of which there is one at each end of the roll. Each end-most bearing unit 16, 16, 16" is exteriorly reduced in diameter at 22 to provide an annular 1.0 shoulder 24 thereon against which the inner end of the adjacent cylindrical sleeve member 18 engages, the outer end of each sleeve member 18 being flanged at 26 for engagement between the shell 28 and the outer race 30 of the adjacent ball bearing unit 20 whose inner race 32 15 is positively fixed to axle 10, 10 as by a set screw 34. A

hole 36 in each. sleeve member 18 permits insertion of a screw driver for driving the set screws 34 after the bearleg elements 16, 16, 16" have been properly positioned on axle 10 or 10.

Inasmuch as curved expander rolls frequently may be drenched with water, as when the sheet being treated is extremely wet, or when a roll is being washed by playing a stream from a hose on it, water must be kept from entering within the roll structures, especially when roller and ball bearings, subject to rusting, are employed. Each end of my improved expander rolls is suitably sealed at 38 against passage of water or moisture into the rolls and, in case of rolls having lubricated bearings, the seals at 38 prevent escape of lubricant out from within the rolls.

Preferably, each bearing element 16, in the Figs. 1 and 2 embodiment, is interiorly grooved as at it) to reduce the area of its surface portions in engagement with the bearing portions 14 of the axle 10. 35 In each of the illustrated embodiments of the invention, a surface sleeve 42, of rubber or other elastic material, resiliently engages around the interior elements throughout the operative length of a curved roll. The surface sleeve 42 may be applied after a roll is otherwise completely assembled excepting one of the end ball-bearing units 20. With the other end ball-bearing unit 20 fixed to the axle and serving as a stop, and with the hearing elements, spacer sleeves, etc., in place on the axle and held against axial travel by the fixed stop 20, the surface sleeve 42 may be stretched to a diameter for being engaged over the end-most bearing element 16, 16', 16 at that end where the end ball-bearing unit 20 is absent. The surface sleeve 42 is then gradually drawn and worked along the curved roll until it embraces all of the heating elements 16, in the Figs. 1 and 2 form, or all of the bearing elements 16' and spacing sleeves 19, in the Figs. 3 and 4 form, or all of the bearing elements 16" in the Fig. 5 form. Also, the surface sleeve embraces the relatively long sleeve 18 reaching inward from the fixed ballat. bearing unit 2t), with its end butted against the fixed ballbearing unit 20. Then, the other end ball-bearing 20 is applied, with its sleeve 18 being forced within the surface sleeve 42 until its end is stopped against the shoulder 24- of the end-most bearing element, after which the adjacent end portion of the surface sleeve is forced inward J enough to uncover the sleeve opening 36 through which set screw 34 may be inserted and screwed tight to fix this last applied ball-bearing unit 20 to the axle. The end portion of the surface sleeve 42 then is released into butting relation to the unit 20.

In each case, the surface sleeve 42 resiliently embraces and ties together interior elements of the roll for rotation in unison, and bridges the spaces between adjacent interior elements.

The surface sleeve 42, if desired, may be of the invertible type as disclosed in Patent No. 2,582,280, granted January 15, i952, to John D. Robertson, in which case the sleeve would be drawn over the bearing elements 16 in the manner shown and described in the said patent.

it is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty exist in the invention disclosed.

I claim as my invention:

1. An expander roll comprising a rigid cross-sectionally round axle having spaced annular grooves therein separating cylindrical bearing portions of the axle, said axle having a slight bend therein at at least some of said grooves, and the accumulation of bends at the grooves providing predetermined general curvature along a major part of the extent of the axle, a series of elements rotatable on the axle and distributed along said generally curved part of the extent thereof, said rotatable elements having bearings on said axle only at said cylindrical bearing portions thereof, and a resilient flexible surface sleeve embracing all of said rotatable elements and connecting them for unitary rotation with the surface sleeve about said generally curved portion of the axle.

2. An expander roll comprising a rigid cross-sectionally round axle having spaced annular grooves therein separating cylindrical bearing portions of the axle, said axle having a slight bend therein at each of said grooves, and the accumulation of bends at the grooves providing predetermined general curvature along a major part of the extent of the axle, generally cylindrical bearing elements threaded on the axle in end to end relation, means maintaining said bearing elements against any appreciable travel along the axle, and a resiliently flexible surface sleeve elastically embracing all of said bearing elements and connecting them for unitary rotation with the surface sleeve about said generally curved major part of the extent of the axle, each said bearing element being in direct bearing engagement with a said cylindrical bearing portion of the axle.

3. An expander roll comprising a rigid cross-sectionally round axle having spaced annular grooves therein separating cylindrical bearing portions of the axle, said axle having a slight bend therein at at least some of said grooves, and the accumulation of bends at the grooves providing predetermined general curvature along a major part of the extent of the axle, a multiplicity of elements rotatably mounted in end to end relation along said generally curved part of the extent of the axle, a bearing unit at each said cylindrical bearing portion of the axle, each said bearing unit being fixed within one of said rotatable elements in bearing coaction with a said cylindrical bearing portion of the axle, each said annular groove in the axle having extent along the axle greater than the length of each said bearing unit, whereby a said element, with a said bearing unit fixed therein, may be moved during assembly of the roll, from a said cylindrical bearing portion of the axle to bring the bearing unit into a said annular groove wherein the hearing unit may be tilted into axial alignment with the next adjacent cylindrical bearing portion of the axle preparatory to being moved thereon, and a resilient flexible surface sleeve embracing all of said rotatable elements and connecting them for unitary rotation with the surface sleeve about said generally curved portion of the axle.

4. In a roll having at least one longitudinally curved portion of substantial length, a rigid cross-sectionally round axle extending throughout the length of the roll and having a multiplicity of relatively short straight bearing portions and a multiplicity of slight bends of which one is located between each two adjacent straight bearing portions, each said bend being so relatively slight that the axes of each two adjacent straight bearing portions are relatively displaced out of alignment only from one to five degrees whereby each said bend contributes but a small fractional part of the roll curvature provided cumulatively by the said multiplicity of bends.

5. A roll having at least one longitudinally curved portion of substantial length comprising a rigid crosssectionally round axle extending throughout the length of the roll and having a multiplicity of relatively short straight bearing portions and a multiplicity of slight bends of which one is located between each two adjacent straight bearing portions, the number of said straight bearing portions and slight bends being so relatively large that the curvature introduced at each of said bends is but a small fraction of the roll curvature provided cumulatively by said multiplicity of bends.

6. A roll having at least one longitudinally curved portion of substantial length comprising a rigid crosssectionally round axle extending throughout the length of the roll and having a multiplicity of relatively short straight bearing portions and a multiplicity of slight bends of which one is located between each two adjacent straight bearing portions, the number of said straight bearing portions and slight bends being so relatively large, and the length of each of at least a majority of said straight bearing portions being so relatively short that the roll curvature appears to be substantially continuous throughout the longitudinally curved portion of the roll.

References Cited in the file of this patent UNITED STATES PATENTS 1,140,546 Ugnon May 25, 1915 2,415,864 Birch Feb. 18, 1947 2,560,039 Harlow, Jr. July 10, 1951 

